oss-sec mailing list archives

Re: please verify unusual x.509 constraints are handled


From: Ludwig Nussel <ludwig.nussel () suse de>
Date: Wed, 27 Jun 2012 15:39:51 +0200

Tavis Ormandy wrote:
List, just an FYI, I've noticed a Korean CA appears to always set the cA
bit in the X.509 basicContraints, then uses pathLenConstraint and
keyUsage bits to restrict the results.
[...]
While arguably the X.509 specifications permit this, I find it hard to
believe that these bits are checked consistently by all implementations.
AFAICT, GnuTLS does not check these constraints, but OpenSSL does.

One thing I always wonder when x509 certificates come into play is
where to draw the line between missing feature and vulnerability.

cu
Ludwig

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